Carbureter.



SIDNEY JOHN ROBINSON, or SYDNEY, New SOUTH WALES, AUSTRALIA.

cARBURnrEI-t.

Specification of Letters Patent.

Patented Apr. 9, 1918.

Applcationled December 16, 1915. Serial No. 67,092.

To all whom z'z may concern.'

Be it known that I, SIDNEY JOHN ROBIN- soN, subject of the King of Great Britain and Ireland, residing at 1 .Vaimea avenue, l/Voollahra, Sydney, New South lVales, Australia, have invented certain new and useful Improvements in Carbureters, of which the following is a specification.

This invention relates to carbureters of the jet type for operating with volatile oil fuel, and it consists in improvements associated y with the choke tube having for their object to control the feed of fuel and air in predetermined relation to the engine induction under all running conditions, and furthermore to secure a good mixture of the air and vaporized fuel.

In the accompanying drawing, Figure 1 is a vertical section through the mixing chamber and part of the float chamber of a standard type of carbureter having my invention applied thereto; Fig. 2 is a vertical section through the mixing chamber of a carbureter having my invention applied thereto, and the spring loading of the valve arranged with a manual control; and Fig. 3 is a detail fragment section illustrating the position of the choke tube like that shown in Fig. 1, when said tube vis lifted by engine suction.

It is obviously immaterial to thefunctioning. of the choke tube how the spring loading is applied to it. Where a variable control is desired the most convenient arrangement is thatV shown in Fig. 2, but where the carbureter is calibrated beforehand and control is not permitted to the user, the most convenient arrangement is that shown in Figs. 1 and 3.

A is the fuel jet nozzle, whichis in practice larger in bore than required for the maximum capacity of the carburetor. B is a fuel control needle valve fitting into the Core of the jet nozzle A and working through a stuliing box C. D is the fuel supply duct from the float chamber or other reservoir.

In the lower part of the mixing chamber E, a sleeve F is fitted neatly and secured by screws G, so that it will be immovable under running conditions, or the mixingY chamber may be bored to two diameters. The bottom end of the mixing chamber .is open as shown in Fig. 1, or is fitted with a cap with lateral air admission openings H as shown in Fig. 2. The choke tube J is cylindrical externally and formed with a collar K near its lower end. Said collar K is a. free sliding fit for the sleeve F, while the neck collar f on the sleeve F forms a working face for the ported upper part of the choke tube. The choke tube is thus slidable vertically inthe sleeve F and it is ported laterally and centrally. The fuel nozzle jet A is located centrally and longitudinally within the choke tube and is fixed. The location of the choke tube in the mixing chamber is determined by the degree of the engine suction which operates to lift the choke tube against the pressure of the helical spring L,fwhich is in compression at one end against the collar f and at the other end against the collar K, which spring normally tends to keep the choke tube down against the collar ring M which is supported on a sprung-1n check ring N. The interiorv of the choke tube is cylindrical inV its lower part and tapered in its upper part, terminating in the head in the central port O which surrounds the tip of the nozzle A when the choke tube is in the lowermost position as shown in Fig. 1, which `is the idling or slow running position of thevtube. The choke tube J is formed at its upper part with a number of annular grooves T, U, V, W, X, at right angles to the axis of the tube, which grooves leave corresponding rings or flanges l. The groovesV are preferably formed of progressively increasing depth, as shown particularly in Fig. 1, so as to correspond with .the diminishing cross-section of the tapered portion of the central passageV O. The tube is also formed with ports 2 extending laterally from the central passage O between the successive rings or flanges l, as will be clearly seen from the drawings, these ports being of progressively increasing area downwardly.v Instead of' the .secret fixed calibrated spring L, a helical springP as in Fig. 2 may be located in the .upper part 0f the mixing chamber bearing on the top of the choke tube and taking its abutment against' the plunger Q, the vertical position of which is adjustable by a bell crank R fitted with a manual pull wire S or other convenient control. By moving the lever R, the position of the plunger Q is adjusted, and consequently the tension on the spring P. IVhen this tension is increased, then for any given degree of engine suction the choke tube ywill rise to less height than formerly, whereas, contrari-wise, when the tension on the spring I is diminished by allowing the plunger Q to rise, the choke tube will be drawn proportionately higher' up into the larger diameter portion of the mixing chamber. Y is the induction lcontrol throttle valve, usually located in the upper` part of the mixing chamber.

ln the idling vor slow running position of the device, as shown in Figs. l and'Q, the choke tube is in its lowermost position and air is admitted to the mixing chamber only through the central port or passage 0, and the concentration of the draft inthe top part around the fuel nozzle then has the effect of procuring a rich mixture, the quantity of air admitted being a minimum. ln the running positions of the device the choke tube is sucked upwardlyT more or less into the mixing chamber by the induction draft, as indicated in Fig. 3, and as the tube rises the lateral ports 2 are opened successively directly into the mixing chamber E, the air then passing into the mixing chamber not only through the central passage O, but also through these lateral ports 2 or through as many of them as yare exposed above the collar f of the sleeve F. t will also be noted that as the choke tube rises the area of the annular air space around the fuel nozzle becomes progressively larger with the result that the proportion of fuel to air is diminished, but the quantum of fuel is maintained sufficient for power requirements` until at ex reine throttle opening when the choke tube is lifted to its uppermost position the thinnest working mixture is obtained.

rl`he amount of fuel drawn from the jet is proportioned to the degree of vacuum surrounding the jet at any particular position, and that degree of vacuum is determined by the relation of the degree of vacuum caused by engine suction to the internal area of that zone of the choke tube which for the time being surrounds the nozzle point. The fuel so drawn from the nozzle is brought into the lower part of the mixing chamber with the air draft, being subdivided between the several'port openings and thoroughly intermingled, with the result that a vapor mixtureV of practical uniform consistency is procured. l p

W'hat l claim as my invention and desire to Isecure by Letters Patent is:

l. A carbureter comprising a mixing chamber having ka constrictedy portion therein, a single valve member substantially Ifitting said constricted portion and movable longitudinally of the mixing chamber under 'enginel suction, and having a central longitudinal passage therethrough directly communicating at all times with said chamber, and a fuel nozzle arranged longitudinally within said central passage, said valve 'member having a plurality of ports extending laterally from said central passage and nor nally closed by said constrcted portion,

.ports as the Valve .moved successively opening directly into the mixing chamber adjacent the point of communication of the central passage therewith, said ports being of considerably greaterl dimension circum ferentially than longitudinally.

2. A carbureter comprising a mixing chamber having a constricted portion there in, a valve member substantially fitting said constricted portion and movable longitudinally of the mixing chamber under engine suction, and having a central longitudinal passage therethrough, a fuel nozzle arranged longitudinally withinsaid central passage, said valve member having a plurality of ports extending laterally from. said central passage and normally closed by said constricted portion but adapted to succesfsively open directly into the mixing chamber as the valve is moved, spring means re sisting the movement of the valve member under the engine suction, and means for veffecting adjustment of said spring means from a distant point.

3. A carbureter comprising a mixing .chamber having a constrictcd portion there in, a valve member substantially fitting said constricted portion and movable longitudinally of themixing chamber under engine suction, and having Va central longitudinal passage therethrough, and a fuel nozzle ar'-V ranged longitudinally within said centra-l passage, said valve member being grooved at right angles to its axis to form rings and having a plurality of ports extending later.- allyl from said central passage between successive rings, said ports being normally closed by said constricted portion but adapted to successively open directly into the mixing chamber as the valve is moved.

el. A carbureter comprising a mixing chamber having a constricted portion therein, a valve member substantially fitting said constricted portion and movable longitudinally of the mixing chamber under engine suction, and having a central longitudinal passage theretl'irough diminishing in cross sectional area, and a fuel nozzle arranged longitudinally within said central passage with its outlet adjacent the narrowest part thereof, said valve member being grooved at right angles to its axis to form rings and having a plurality of ports extending laterally from said centr-al passage between successive rings, said ports being normally closed by said eonstricted portion but adapted to successively open directly into the mixing chamber as the valve is moved.

5. A. carbureter comprising in combination, a chamber having portions of different vcross sectional area, the'lar-ger portion serv ing as a mixing chamber, a single valve member normally lying wholly'within, and fittting the smaller pertion lof the chamber and adapted yto he drawn .into the mixing 'chainv A ber having a central longitudinal passage communicating with said mixing chamber, and ports extending laterally outwardly from said passage, normally closed by the wall of the smaller portion of the chamber but adapted to successively open directly into the mixing chamber as the valve is drawn thereinto, a fuel nozzle extending` into said passage, means for supplying air to said passage, and means operable from a distant point for adjustably controlling the movement of the valve member by the engine suction.

6. A carbureter comprising in combination, a chamber having portions of dilierent cross sectional area, the larger portion serv ing as a mixing chamber, a single valve member normally lying wholly Within, and fitting the smaller portion of the chamber and adapted to be drawn into the mixing chamber by the engine suction, said valve member having a central longitudinal passage communicating with and tapering toward said mixing chamber, and being grooved at right angles to its axis to form rings, and ports extending laterally outwardly from said passage between said rings, normally closed by the Wall of the smaller portion of the chamber but adapted to successively open directly into the mixing chamber as the valve is drawn thereinto, `a

fuel nozzle extending into said passage and means for supplying air tosaid passage.

Y 7. A carbureter comprising a mixing chamber having a constricted portion therein, a single valve member substantially litting said constricted portion and movable longitudinally of the mixing chamber under engine suction, and having a central longitudinal passage therethrough directly communicating at all times with said chamber, and a fuel nozzle arranged longitudinally within said central passage, said valve member having a plurality of ports extending laterally from said central passage and normally closed by said constricted portion, said ports being of considerably greater dimension circumferentially than longitudinally and adapted to successively open directly into the mixing chamber as the valve is moved.

In testimony whereof I have aiixed my signature in presence of two witnesses.

Witnesses:

E. F. WILxEs, W. I. DAVIS.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

